In the production of silicon crystals grown by the continuous Czochralski method, polycrystalline silicon is melted within a crucible of a crystal pulling device to form a silicon melt. A seed crystal is then lowered to the melt and slowly raised back up. As the seed crystal is continuously grown from the melt, solid polysilicon such as granular polysilicon is added to the melt to replenish the melt. The feed rate of the additional solid polysilicon added to the melt is typically controlled to maintain process parameters. In the production of silicon crystals grown by the batch Czochralski method, solid polysilicon, such as chunk polysilicon, is not added to the melt while the seed crystal is grown but is added between sequential growing processes. The feed rate of the additional polysilicon is controlled to maintain process parameters.
The solid polysilicon added to the crucible melt is typically granular polysilicon, and it is fed into the crucible using a polysilicon feeder that is optimized for use with granular polysilicon. In some cases, solid polysilicon added to a crucible melt is chunk polysilicon. Chunk polysilicon has a greater size (e.g., in at least one dimension) than that of granular polysilicon. Chunk polysilicon is fed into a crucible using a polysilicon feeder optimized for use with chunk polysilicon. A more satisfactory apparatus and method for feeding either chunk or granular polysilicon is needed.
This Background section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present disclosure, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.